1. Field of the Invention
The present invention relates to a height compensation device to compensate for car body height loss when the rail engaging support wheels of the railway truck are re-profiled after wear.
2. Description of Prior Art
It is known to provide height adjusting elements, such as shim pads, between the truck assembly and the railway car body to compensate for height loss due to grinding of the rail engaging support wheels of the truck assembly when these become worn Such height adjusters are, for example, described in co-pending U.S. application Ser. No. 515,417 filed on Apr. 27, 1990, now U.S. Pat. No. 5,048,427 issued on Sep. 17, 1991 and entitled Railway Truck Assembly with Side Bearing Height Adjuster. That patent application also discloses the importance of the provisions of such shim pads and the disadvantages and problems in replacing these pads. However, in that patent application, and also in other known prior art height adjusting devices, it is always necessary to add an additional shim plate or to replace an existing shim plate to effect the height adjustment. A problem with such height adjusters is that they can become dislodged during use and lost as they are not positively engaged, causing excessive damage and wear to the wheels. Because these adjusters are separate pieces, they are often lost in the retrofitting garages and errors can arise in selecting an improper shim pad when effecting a shim replacement. They are also difficult to install as disclosed in the referenced application.